Cloud Hosting

Highly flexible, but not without its own set of issues

By
David Adams
on
16 July, 2013

Cloud hosting, as offered by the bigger hosting providers like Amazon (the
online retailer and pioneer of cloud hosting), Rackspace and others, is hosting
where instead of buying the use of a server on an ongoing basis, you buy an
amount of server power and pay for it by the hour or day. If you're
thinking that sounds a bit like a Virtual Private Server, you'd be right.
The difference is that there is no long-term commitment. You can
increase or decrease the server power at any time (though beware; though all
cloud hosting providers tout this as a benefit, it can be a complex and time
consuming operation - you generally can't just push a button and have more
power) and you can switch the whole thing off and incur no further fees
until you switch it back on again. Some call it a "pay as you go"
service.

Cloud servers work by virtualisation, like a Virtual Private Server, where
you're given a slice of computing power, disk storage, etc. Your usage is
segregated from other users and you get full access to the server, on which
you can run pretty much anything you want. So you get lots of
flexibility. On top of this great flexibility the best thing is
you only pay for the resources you choose. If you're service is
growing you can keep expanding without having to invest a lot in advance
(and possibly even in advance of you being certain it will grow!).

That all sounds really good, but in reality, it's not quite that simple.
For a given amount of computing power, cloud servers individually
are more expensive. A server hosted by Amazon which is kept
up and running all day every day (let's face it, most websites aren't
switched off at night and weekends!) with a given amount of processing
power, a given amount of memory and disk space will probably cost
more per month than a renting a traditional dedicated server and is
completely unmanaged - you will need technical expertise to set it up and
run it. With a cloud server you tend to pay for everything, the
server power, the disk storage, the data transfer, etc. This makes
comparing prices difficult and also means you cannot know in advance
exactly how much you'll spend.

The power of cloud hosting comes when you have multiple servers and you
don't need all of them on all the time. Most smaller websites run
on a single server, or sometimes two, but they both need to be on all the
time to keep the site running. So in this instance cloud hosting
will probably cost more. However, if you run a larger site with
definite patterns of usage you can use a cloud hosting system to allow
you to add and remove extra hardware when you need it and only when you
need it. For example, let's say you run a website for school
children; it might be very quiet in the week but busier at weekends and
through the school holidays. You could use a cloud server system so
that you had one server online all the time, but at weekends and holiday
times you could add a couple of extra servers to cope with your increased
traffic. Doing that would be much cheaper than having three servers
constantly running when two of them are hardly doing anything most of the
time.

Another advantage of cloud servers is when you only need to run your site
for a short period. Maybe you're doing a promotion which only lasts
a month - rather than renting a server for a whole year you can rent a
cloud server for just that month. Or perhaps you want to experiment
with a new system. Cloud serving is perfect for this - we've been
known to rent a server for just a couple of hours to get a job done.
Even though we have two data centres with lots of servers it's
actually easier and quicker for us to just rent something from Amazon for
a short period than set up a new server.

Cloud servers can make a great backup mechanism. Rather than paying
to have duplicate hardware sitting waiting in case your primary hardware
fails, you can get everything set up on a cloud server somewhere then
switch it off. You incur no costs (other than perhaps a minimal
amount for storage) but if your primary server fails you can power up
your cloud server and be back online in far less time than it would take
to repair or replace your hardware.

Don't under estimate the complexity of using cloud servers. They
are generally only suitable for those with plenty of technical knowledge,
particularly if you want to take full advantage of all they can offer.
Cloud servers can and do fail, just like any other servers.
If you want a robust system you will need to have designed in
contingencies which are likely more complex than with simpler, dedicated
servers. When Amazon's have had problems with their cloud
hosting many of their customers have been caught out by thinking they
could just fire up new servers in the same data centre, but instead the
whole data centre was not responding. Only those that had designed
their service to be transferable between data centres were able to stay
online.

In summary, cloud hosting is wonderfully flexible and can be cost
effective if you're running a large and complex website, but don't
underestimate the complexity of managing a good cloud
infrastructure; if you're running a more modest site on one or two
servers it's unlikely to be cost effective.